Matti Williams joined Warriors ahead of the 2016/17 season.
The versatile forward made his Club debut away at Leicester Tigers in October 2016 before going on to make seven appearances during the campaign and a further seven in 2017/18.
Born in East London, South Africa, Williams can play at both flanker and hooker.
He moved to Northampton Saints in 2013 and soon made his first-team debut for them against Gloucester Rugby in the LV=Cup.
A broken leg on his Aviva Premiership debut against London Irish cut short his first season at the club, but the hooker returned to action in 2014/15 and went on to make seven top-flight appearances during his time at Franklin's Gardens.